48 Juvenile dermatomyositis: the experience of Military Pediatrics Department of Tunis

Abstract Background Juvenile dermatomyositis (JD) is a rare autoimmune disorder characterized by a non-infectious inflammatory state affecting of the muscles and skin associated with a vasculopathy which represents the essential of its physiopathogenesis. Objectives To review the clinical and biological diagnosis of DMJ as well as its evolution under treatment based on the cases of two patients at the Military Pediatrics Department of Tunis. Observations Case 1: This was a three-and-a-half-year-old child with a history of a simple febrile seizure, admitted for a skin rash and myalgia that had been evolving for eight months. Skin examination revealed an erythematous rash of the face and upper eyelids with erythematous papular lesions in front of the proximal interphalangeal joint recalling Gottron's papules. Muscle testing was in favor of a proximal deficiency and the electromyogram (EMG) revealed a diffuse myogenic process more pronounced on the proximal muscles without signs of myositic activity. Biology analysis did not reveal a biological inflammatory syndrome but rather increased muscle enzymes levels up to 3- and 4-times normal values. On the immune status report, there was no evidence of DMJ-specific autoantibodies (ASM), but the anti-SRP antibodies associated with myositis were present. The diagnosis of DMJ was established in view of the association of typical cutaneous signs and 3 muscular signs (proximal deficit, elevation of muscle enzymes, myogenic tracing) and an evaluation of the activity of the disease according to a standardized scale by the Childhood Myositis Assessment Scale (CMAS) was required (which was at 7/52). Treatment with corticosteroids and methotrexate was started after a pretherapeutic evaluation and regular check-ups of the child showed a clear improvement of clinical and muscular signs (CMAS became at 41/52). Case 2: A 7-year-old boy, with no previous pathological history, admitted to our department to explore his gait disorder associated to erythematosquamous lesions. At the dermatological inspection, a localized erythema was noted on the upper eyelids, the nose, the cheeks and the chin area, as well as erythematosquamous lesions on the interphalangeal joints, metacarpophalangeal joints, elbows and knees (Gottron papules). The gait was waddling, the EMG was in favor of myogenic disorder and the muscular testing revealed a proximal muscular affection. The biology results showed an elevation of CPK and LDH to 1.5 times the normal values and a sedimentation rate at 40 mm/h. The antibodies determination showed the existence of anti-NXP2 antibodies specific to myositis. The progression under treatment (corticosteroids, methotrexate and adjuvant treatment) was favorable with a CMAS score of 39 (CMAS was 11 when admitted). The persistence of squamous lesions recalling calcinosis on the dorsal surfaces of the forearms was well correlated with the presence of anti-NXP2 antibodies. Conclusion The positive diagnosis of DMJ in a child must be based on clinical and biological arguments. The immunological characterization of DMJ should be an important element in the disease management because it can explain the lesions associated with certain myositis specific antibodies as well as their evolution, which implies a particular follow-up depending on the detected antibodies (risk of cancer in anti-NXP2 AC positive patients)


Background
Childhood-onset systemic lupus erythematosus (c-SLE) is the prototype of a multisystemic, inflammatory, heterogeneous autoimmune condition, characterized by simultaneous or sequential organ involvement. Compared with the adult onset form, c-SLE is thought to have a worse prognosis.

Objectives
To review the epidemiological, and bio-clinical, characteristics of a c-SLE case series.

Methods
The files of patients diagnosed as c-SLE in the pediatrics department of Monastir, Tunisia from January 2004 to March 2022 were reviewed. Mean and standard-deviations were used to express normallydistributed variables, as verified by the Kolmogorov-Smirnov statistical test.

Results
Fourteen patients were collected. Female to male ratio was 6:1. Mean ages at lupus onset and diagnosis were 9.9 AE 1.4 years, [5-13.8 years] and 10.75 AE 2.3 years [6-14 years], respectively. Only two children had a family history of autoimmune disease. The initial admission was motivated primarily by skin and musculoskeletal manifestations, in 64.3% and 51.7% of cases, respectively. General signs (fever, asthenia) were observed in 35.7% of cases, hematological and gastrointestinal manifestations in 28.6% of cases each. In 3 cases, upper gastric endoscopy was performed prior to admission, in view of abdominal pain and vomiting. The physical examination noted various anomalies. Malar rash (50%) and discoid lupus (28.6%) were the most frequent cutaneous manifestations, while skin biopsy was performed in three cases, all favorable for lupus. The musculoskeletal manifestations comprised arthralgia (71.4%), arthritis and myositis (14.3% each). Hematological manifestations included thrombocytopenia and leukopenia in 4 cases each, as well as 3 cases of auto-immune hemolytic anaemia and splenomegaly. Renal manifestations were dominated by proteinuria in 7 cases, followed by hematuria in 6 cases, and 2 cases of hypertension (associated with renal failure in one case). The renal biopsy was performed in one case showed a stage-2 lupus nephritis. Pleural effusion was observed in 3 cases, 3 cases of pneumonia, 2 cases of pericarditis, one case of myo-pericarditis and one case of central nervous system (CNS) lupus. Relevant results of the laboratory workup are illustrated in the following The formal diagnosis of SLE was established according to the ACR-1997 criteria in 7 cases (50%), the SLICC-2012 in 4 cases (28.6%) and EULAR/ACR-2019 in 3 cases (21.4%). The c-SLE diagnosis was associated with coeliac disease and Hashimoto thyroiditis in one case each.
The therapeutic management was based on corticosteroids in 11 cases, followed by hydroxychloroquine in 3 cases, while cyclophosphamides and immunoglobulin were used for one case each. The outcomes were heterogeneous. Among 11 patients with sufficient follow-up, 6 cases of remission and 2 cases of relapse were noted. Major adverse events were not infrequent: one case each of cardiac tamponade, macrophage activation syndrome and severe CNS lupus were observed, all fatal.

Conclusion
Childhood-onset systemic lupus is a challenging disease, both to diagnose and to treat. The development of new criteria of higher specificity and sensitivity has greatly helped identify the incomplete types of lupus and allow for early stage diagnosis, and therefore prevent the serious complications of the disease. Background Juvenile dermatomyositis (JD) is a rare autoimmune disorder characterized by a non-infectious inflammatory state affecting of the muscles and skin associated with a vasculopathy which represents the essential of its physiopathogenesis.

Objectives
To review the clinical and biological diagnosis of DMJ as well as its evolution under treatment based on the cases of two patients at the Military Pediatrics Department of Tunis.

Observations
Case 1: This was a three-and-a-half-year-old child with a history of a simple febrile seizure, admitted for a skin rash and myalgia that had been evolving for eight months. Skin examination revealed an erythematous rash of the face and upper eyelids with erythematous papular lesions in front of the proximal interphalangeal joint recalling Gottron's papules. Muscle testing was in favor of a proximal deficiency and the electromyogram (EMG) revealed a diffuse myogenic process more pronounced on the proximal muscles without signs of myositic activity. Biology analysis did not reveal a biological inflammatory syndrome but rather increased muscle enzymes levels up to 3-and 4times normal values. On the immune status report, there was no evidence of DMJ-specific autoantibodies (ASM), but the anti-SRP antibodies associated with myositis were present. The diagnosis of DMJ was established in view of the association of typical cutaneous signs and 3 muscular signs (proximal deficit, elevation of muscle enzymes, myogenic tracing) and an evaluation of the activity of the disease according to a standardized scale by the Childhood Myositis Assessment Scale (CMAS) was required (which was at 7/52). Treatment with corticosteroids and methotrexate was started after a pretherapeutic evaluation and regular check-ups of the child showed a clear improvement of clinical and muscular signs (CMAS became at 41/52). Case 2: A 7-year-old boy, with no previous pathological history, admitted to our department to explore his gait disorder associated to erythematosquamous lesions. At the dermatological inspection, a localized erythema was noted on the upper eyelids, the nose, the cheeks and the chin area, as well as erythematosquamous lesions on the interphalangeal joints, metacarpophalangeal joints, elbows and knees (Gottron papules). The gait was waddling, the EMG was in favor of myogenic disorder and the muscular testing revealed a proximal muscular affection. The biology results showed an elevation of CPK and LDH to 1.5 times the normal values and a sedimentation rate at 40 mm/h. The antibodies determination showed the existence of anti-NXP2 antibodies specific to myositis. The progression under treatment (corticosteroids, methotrexate and adjuvant treatment) was favorable with a CMAS score of 39 (CMAS was 11 when admitted). The persistence of squamous lesions recalling calcinosis on the dorsal surfaces of the forearms was well correlated with the presence of anti-NXP2 antibodies.

Conclusion
The positive diagnosis of DMJ in a child must be based on clinical and biological arguments. The immunological characterization of DMJ should be an important element in the disease management because it can explain the lesions associated with certain myositis specific antibodies as well as their evolution, which implies a particular followup depending on the detected antibodies (risk of cancer in anti-NXP2 AC positive patients) ii18 E POSTERS